1. Field of the Invention
The field of the invention relates to a method to detect a point of interest (POI) of an aldehyde in a test sample such as a disinfectant. In some embodiments, a device or test strip are used to detect the point of interest of the aldehyde in the test sample.
2. Description of the Related Art
MBTH (3-methyl-2-benzothiazolinone hydrazone hydrochloride) is a well-known aldehyde analysis reagent. Using this reagent, an azine is formed between an aldehyde and MBTH. MBTH is also oxidized by an oxidizing agent such as ferric chloride to another species, which combines with the azine to form a blue colored formazan structure. This reaction was originally described by Sawicki et al. (Sawicki et al. (1961) Analytical Chemistry vol. 33 (1): 93–96) as an extremely sensitive assay for detection of aldehydes in exhaust fumes. The method of Sawicki et al. was subsequently modified to achieve even higher sensitivity to allow detection of aldehydes in air in the parts-per-billion range (Hauser et al. (1964) Analytical Chemistry vol. 36 (3): 679–681).
EP 0 016 578 teaches application of the reaction of MBTH with aldehydes to aqueous samples. The assay was useful with samples in the parts per million range. The MBTH procedure was also adapted for use in seawater samples to measure the formaldehyde given off by the marine methanotroph, Methylomonas pelagica (Eberhardt et al. (1985) Marine Chemistry vol. 17: 199–212). This method has proven very useful in analysis of dilute aldehyde-containing samples. However, for concentrated aldehyde analysis, this method is inconvenient due to the need for dilutions. A new method is proposed here for use of the MBTH procedure with samples which contain higher concentrations of aldehydes such as disinfectants.